Quarry vs Codebasics

Data interview practice that runs entirely on your device. Write real SQL and Python (pandas), get graded instantly, and see exactly why. NEW IN 1.1 • Designed for iPhone Duo: question and editor side by side when open, a focused layout when closed, and it adapts as you fold. • A new native design for iPhone and iPad, in light and dark mode. • 60 new problems: a staff-level data engineering set (gaps and islands, sessionisation, slowly changing dimensions, funnels, retention) and company-style SQL sets. • Clearer results: instant correct / not quite feedback, expected vs. actual tables, and the query plan for your SQL. WHAT'S INSIDE • 168 problems across three tracks: 61 SQL, 22 pandas and 85 Python (algorithms and data structures). • Real execution, real grading. Your output is checked against the expected result, with no self-marking. • Company-style practice. Filter problems written in the style of the company you're interviewing at. • Hints and full solutions when you're stuck. • Difficulty levels from Easy to Hard, grouped by topic. • A free-form Playground for scratch SQL and Python. PRIVATE BY DESIGN No accounts. No analytics. No ads. No tracking. Quarry collects nothing and works fully offline. Built by a working data engineer, for analysts, data engineers, data scientists and software engineers who want a quiet, fast place to actually practice.

Codebasics is the mobile companion to codebasics.io — the e-learning platform trusted by 700,000+ learners and 1.5 million+ YouTube subscribers to build careers in Data Analytics, Data Engineering, and AI Engineering. Whether you're just starting out or upskilling for your next role, Codebasics turns daily practice into real career progress — one skill test, one mock interview, one flashcard at a time. WHAT YOU CAN DO • Career Suitability Test — Answer a few questions to find out which path fits you best: Data Analyst, Data Engineer, or AI Engineer. • Daily Skill Tests — Sharpen your Python, SQL, and Machine Learning skills with 5 new questions every day. Everyone gets the same set, and it rotates through the full question bank over time. • Mock Interview Practice — Practice like it's the real thing with 10 daily questions per career path (5 core + 3 scenario-based + 2 behavioral). • Daily Flashcards — Get one revision flashcard per module every day, tailored to your chosen career path, for quick daily reinforcement. • Bootcamps & Resources — Browse curated learning materials, guides, and Codebasics bootcamps to go deeper on the skills you need. STAY MOTIVATED • Earn XP for every correct answer and every perfect score, and level up from Beginner all the way to Master. • Build a daily streak by practicing every day — miss a day and it resets, so keep coming back. WHY CODEBASICS Codebasics has helped hundreds of thousands of learners — including career switchers and non-IT professionals — land roles at companies like TCS, Deloitte, Oracle, and EY. With instructors bringing 12+ years of industry experience and a track record of 7,000+ five-star reviews, Codebasics is built to get you job-ready, not just certificate-ready. Sign in with your Codebasics account to sync your progress, XP, and streaks across devices. Have questions or feedback? Visit codebasics.io or reach out through the app.